uml: style fixes in arch/um/kernel
[linux-2.6.git] / arch / um / kernel / process.c
1 /*
2  * Copyright (C) 2000 - 2007 Jeff Dike (jdike@{addtoit,linux.intel}.com)
3  * Copyright 2003 PathScale, Inc.
4  * Licensed under the GPL
5  */
6
7 #include <linux/stddef.h>
8 #include <linux/err.h>
9 #include <linux/hardirq.h>
10 #include <linux/gfp.h>
11 #include <linux/mm.h>
12 #include <linux/personality.h>
13 #include <linux/proc_fs.h>
14 #include <linux/ptrace.h>
15 #include <linux/random.h>
16 #include <linux/sched.h>
17 #include <linux/tick.h>
18 #include <linux/threads.h>
19 #include <asm/current.h>
20 #include <asm/pgtable.h>
21 #include <asm/uaccess.h>
22 #include "as-layout.h"
23 #include "kern_util.h"
24 #include "os.h"
25 #include "skas.h"
26 #include "tlb.h"
27
28 /*
29  * This is a per-cpu array.  A processor only modifies its entry and it only
30  * cares about its entry, so it's OK if another processor is modifying its
31  * entry.
32  */
33 struct cpu_task cpu_tasks[NR_CPUS] = { [0 ... NR_CPUS - 1] = { -1, NULL } };
34
35 static inline int external_pid(void)
36 {
37         /* FIXME: Need to look up userspace_pid by cpu */
38         return userspace_pid[0];
39 }
40
41 int pid_to_processor_id(int pid)
42 {
43         int i;
44
45         for (i = 0; i < ncpus; i++) {
46                 if (cpu_tasks[i].pid == pid)
47                         return i;
48         }
49         return -1;
50 }
51
52 void free_stack(unsigned long stack, int order)
53 {
54         free_pages(stack, order);
55 }
56
57 unsigned long alloc_stack(int order, int atomic)
58 {
59         unsigned long page;
60         gfp_t flags = GFP_KERNEL;
61
62         if (atomic)
63                 flags = GFP_ATOMIC;
64         page = __get_free_pages(flags, order);
65
66         return page;
67 }
68
69 int kernel_thread(int (*fn)(void *), void * arg, unsigned long flags)
70 {
71         int pid;
72
73         current->thread.request.u.thread.proc = fn;
74         current->thread.request.u.thread.arg = arg;
75         pid = do_fork(CLONE_VM | CLONE_UNTRACED | flags, 0,
76                       &current->thread.regs, 0, NULL, NULL);
77         return pid;
78 }
79
80 static inline void set_current(struct task_struct *task)
81 {
82         cpu_tasks[task_thread_info(task)->cpu] = ((struct cpu_task)
83                 { external_pid(), task });
84 }
85
86 extern void arch_switch_to(struct task_struct *to);
87
88 void *_switch_to(void *prev, void *next, void *last)
89 {
90         struct task_struct *from = prev;
91         struct task_struct *to = next;
92
93         to->thread.prev_sched = from;
94         set_current(to);
95
96         do {
97                 current->thread.saved_task = NULL;
98
99                 switch_threads(&from->thread.switch_buf,
100                                &to->thread.switch_buf);
101
102                 arch_switch_to(current);
103
104                 if (current->thread.saved_task)
105                         show_regs(&(current->thread.regs));
106                 to = current->thread.saved_task;
107                 from = current;
108         } while (current->thread.saved_task);
109
110         return current->thread.prev_sched;
111
112 }
113
114 void interrupt_end(void)
115 {
116         if (need_resched())
117                 schedule();
118         if (test_tsk_thread_flag(current, TIF_SIGPENDING))
119                 do_signal();
120 }
121
122 void exit_thread(void)
123 {
124 }
125
126 void *get_current(void)
127 {
128         return current;
129 }
130
131 extern void schedule_tail(struct task_struct *prev);
132
133 /*
134  * This is called magically, by its address being stuffed in a jmp_buf
135  * and being longjmp-d to.
136  */
137 void new_thread_handler(void)
138 {
139         int (*fn)(void *), n;
140         void *arg;
141
142         if (current->thread.prev_sched != NULL)
143                 schedule_tail(current->thread.prev_sched);
144         current->thread.prev_sched = NULL;
145
146         fn = current->thread.request.u.thread.proc;
147         arg = current->thread.request.u.thread.arg;
148
149         /*
150          * The return value is 1 if the kernel thread execs a process,
151          * 0 if it just exits
152          */
153         n = run_kernel_thread(fn, arg, &current->thread.exec_buf);
154         if (n == 1) {
155                 /* Handle any immediate reschedules or signals */
156                 interrupt_end();
157                 userspace(&current->thread.regs.regs);
158         }
159         else do_exit(0);
160 }
161
162 /* Called magically, see new_thread_handler above */
163 void fork_handler(void)
164 {
165         force_flush_all();
166
167         schedule_tail(current->thread.prev_sched);
168
169         /*
170          * XXX: if interrupt_end() calls schedule, this call to
171          * arch_switch_to isn't needed. We could want to apply this to
172          * improve performance. -bb
173          */
174         arch_switch_to(current);
175
176         current->thread.prev_sched = NULL;
177
178         /* Handle any immediate reschedules or signals */
179         interrupt_end();
180
181         userspace(&current->thread.regs.regs);
182 }
183
184 int copy_thread(int nr, unsigned long clone_flags, unsigned long sp,
185                 unsigned long stack_top, struct task_struct * p,
186                 struct pt_regs *regs)
187 {
188         void (*handler)(void);
189         int ret = 0;
190
191         p->thread = (struct thread_struct) INIT_THREAD;
192
193         if (current->thread.forking) {
194                 memcpy(&p->thread.regs.regs, &regs->regs,
195                        sizeof(p->thread.regs.regs));
196                 REGS_SET_SYSCALL_RETURN(p->thread.regs.regs.gp, 0);
197                 if (sp != 0)
198                         REGS_SP(p->thread.regs.regs.gp) = sp;
199
200                 handler = fork_handler;
201
202                 arch_copy_thread(&current->thread.arch, &p->thread.arch);
203         }
204         else {
205                 get_safe_registers(p->thread.regs.regs.gp);
206                 p->thread.request.u.thread = current->thread.request.u.thread;
207                 handler = new_thread_handler;
208         }
209
210         new_thread(task_stack_page(p), &p->thread.switch_buf, handler);
211
212         if (current->thread.forking) {
213                 clear_flushed_tls(p);
214
215                 /*
216                  * Set a new TLS for the child thread?
217                  */
218                 if (clone_flags & CLONE_SETTLS)
219                         ret = arch_copy_tls(p);
220         }
221
222         return ret;
223 }
224
225 void initial_thread_cb(void (*proc)(void *), void *arg)
226 {
227         int save_kmalloc_ok = kmalloc_ok;
228
229         kmalloc_ok = 0;
230         initial_thread_cb_skas(proc, arg);
231         kmalloc_ok = save_kmalloc_ok;
232 }
233
234 void default_idle(void)
235 {
236         unsigned long long nsecs;
237
238         while (1) {
239                 /* endless idle loop with no priority at all */
240
241                 /*
242                  * although we are an idle CPU, we do not want to
243                  * get into the scheduler unnecessarily.
244                  */
245                 if (need_resched())
246                         schedule();
247
248                 tick_nohz_stop_sched_tick();
249                 nsecs = disable_timer();
250                 idle_sleep(nsecs);
251                 tick_nohz_restart_sched_tick();
252         }
253 }
254
255 void cpu_idle(void)
256 {
257         cpu_tasks[current_thread_info()->cpu].pid = os_getpid();
258         default_idle();
259 }
260
261 void dump_thread(struct pt_regs *regs, struct user *u)
262 {
263 }
264
265 int __cant_sleep(void) {
266         return in_atomic() || irqs_disabled() || in_interrupt();
267         /* Is in_interrupt() really needed? */
268 }
269
270 int user_context(unsigned long sp)
271 {
272         unsigned long stack;
273
274         stack = sp & (PAGE_MASK << CONFIG_KERNEL_STACK_ORDER);
275         return stack != (unsigned long) current_thread_info();
276 }
277
278 extern exitcall_t __uml_exitcall_begin, __uml_exitcall_end;
279
280 void do_uml_exitcalls(void)
281 {
282         exitcall_t *call;
283
284         call = &__uml_exitcall_end;
285         while (--call >= &__uml_exitcall_begin)
286                 (*call)();
287 }
288
289 char *uml_strdup(const char *string)
290 {
291         return kstrdup(string, GFP_KERNEL);
292 }
293
294 int copy_to_user_proc(void __user *to, void *from, int size)
295 {
296         return copy_to_user(to, from, size);
297 }
298
299 int copy_from_user_proc(void *to, void __user *from, int size)
300 {
301         return copy_from_user(to, from, size);
302 }
303
304 int clear_user_proc(void __user *buf, int size)
305 {
306         return clear_user(buf, size);
307 }
308
309 int strlen_user_proc(char __user *str)
310 {
311         return strlen_user(str);
312 }
313
314 int smp_sigio_handler(void)
315 {
316 #ifdef CONFIG_SMP
317         int cpu = current_thread_info()->cpu;
318         IPI_handler(cpu);
319         if (cpu != 0)
320                 return 1;
321 #endif
322         return 0;
323 }
324
325 int cpu(void)
326 {
327         return current_thread_info()->cpu;
328 }
329
330 static atomic_t using_sysemu = ATOMIC_INIT(0);
331 int sysemu_supported;
332
333 void set_using_sysemu(int value)
334 {
335         if (value > sysemu_supported)
336                 return;
337         atomic_set(&using_sysemu, value);
338 }
339
340 int get_using_sysemu(void)
341 {
342         return atomic_read(&using_sysemu);
343 }
344
345 static int proc_read_sysemu(char *buf, char **start, off_t offset, int size,int *eof, void *data)
346 {
347         if (snprintf(buf, size, "%d\n", get_using_sysemu()) < size)
348                 /* No overflow */
349                 *eof = 1;
350
351         return strlen(buf);
352 }
353
354 static int proc_write_sysemu(struct file *file,const char __user *buf, unsigned long count,void *data)
355 {
356         char tmp[2];
357
358         if (copy_from_user(tmp, buf, 1))
359                 return -EFAULT;
360
361         if (tmp[0] >= '0' && tmp[0] <= '2')
362                 set_using_sysemu(tmp[0] - '0');
363         /* We use the first char, but pretend to write everything */
364         return count;
365 }
366
367 int __init make_proc_sysemu(void)
368 {
369         struct proc_dir_entry *ent;
370         if (!sysemu_supported)
371                 return 0;
372
373         ent = create_proc_entry("sysemu", 0600, &proc_root);
374
375         if (ent == NULL)
376         {
377                 printk(KERN_WARNING "Failed to register /proc/sysemu\n");
378                 return 0;
379         }
380
381         ent->read_proc  = proc_read_sysemu;
382         ent->write_proc = proc_write_sysemu;
383
384         return 0;
385 }
386
387 late_initcall(make_proc_sysemu);
388
389 int singlestepping(void * t)
390 {
391         struct task_struct *task = t ? t : current;
392
393         if (!(task->ptrace & PT_DTRACE))
394                 return 0;
395
396         if (task->thread.singlestep_syscall)
397                 return 1;
398
399         return 2;
400 }
401
402 /*
403  * Only x86 and x86_64 have an arch_align_stack().
404  * All other arches have "#define arch_align_stack(x) (x)"
405  * in their asm/system.h
406  * As this is included in UML from asm-um/system-generic.h,
407  * we can use it to behave as the subarch does.
408  */
409 #ifndef arch_align_stack
410 unsigned long arch_align_stack(unsigned long sp)
411 {
412         if (!(current->personality & ADDR_NO_RANDOMIZE) && randomize_va_space)
413                 sp -= get_random_int() % 8192;
414         return sp & ~0xf;
415 }
416 #endif
417
418 unsigned long get_wchan(struct task_struct *p)
419 {
420         unsigned long stack_page, sp, ip;
421         bool seen_sched = 0;
422
423         if ((p == NULL) || (p == current) || (p->state == TASK_RUNNING))
424                 return 0;
425
426         stack_page = (unsigned long) task_stack_page(p);
427         /* Bail if the process has no kernel stack for some reason */
428         if (stack_page == 0)
429                 return 0;
430
431         sp = p->thread.switch_buf->JB_SP;
432         /*
433          * Bail if the stack pointer is below the bottom of the kernel
434          * stack for some reason
435          */
436         if (sp < stack_page)
437                 return 0;
438
439         while (sp < stack_page + THREAD_SIZE) {
440                 ip = *((unsigned long *) sp);
441                 if (in_sched_functions(ip))
442                         /* Ignore everything until we're above the scheduler */
443                         seen_sched = 1;
444                 else if (kernel_text_address(ip) && seen_sched)
445                         return ip;
446
447                 sp += sizeof(unsigned long);
448         }
449
450         return 0;
451 }
452
453 int elf_core_copy_fpregs(struct task_struct *t, elf_fpregset_t *fpu)
454 {
455         int cpu = current_thread_info()->cpu;
456
457         return save_fp_registers(userspace_pid[cpu], (unsigned long *) fpu);
458 }
459